DESCRIPTION: (Applicant's abstract) The development of a continuous-flow magnetic cell sorter is proposed, with the Phase II goal of producing a commercially viable product. The primary commercial application of the device would be for the isolation of hematopoietic stem cells for re-transplantation after cancer therapies, using colloidal immunomagnetic labels. There are also potential secondary commercial applications, including the detection of rare circulating cancer cells in blood. The main success criteria for the stem cell application are to maintain a throughput (10/7 cells/s) sufficient for practical clinical use, with purity and recovery fraction exceeding 60%. Preliminary work has been done at the CCF on a smaller scale experimental laboratory prototype. The specific aims of this proposal are to fully evaluate and characterize the existing prototype, to optimize the design of the quadrupole magnet, and to optimize the fluid flow design. Challenges in the design optimization include the practical attainment of high-strength fields and the precise control of higher-volume pumps. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE